code: def test_explode_inner_null() -> None:
      expected = pl.DataFrame(
          {"A": [None, None]}, schema={"A": pl.Null}
      )
      out = pl.DataFrame(
          {"A": [[], []]}, schema={"A": pl.List(pl.Null)}
      ).explode("A")
      assert_frame_equal(out, expected)
  
imports: from __future__ import annotations
  import pyarrow
  import pytest
  import polars
  import polars.selectors
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 20 for calling a global function with example usage: test_explode_inner_null() without return types